1. Field of the Invention
The present invention relates to CO.sub.2 jet spray nozzles, and more particularly, to CO.sub.2 jet spray nozzles having multiple orifices.
2. Description of Related Art
The related prior art of CO.sub.2 jet spray nozzles is believed to involve the use of a variable orifice. Despite much literature on the subject, this aspect has not been well explained or documented. Exact geometries of the nozzles vary and can be considered proprietary by each manufacturer. Fixed orifice nozzles are disclosed in U.S. Pat. No. 4,806,171, issued to Whitlock et al., and U.S. Pat. No. 4,962,891, issued to Layden. In each case a set of two (consecutive) orifices is given as essential to good jet spray (snow) production. In both cases the source of CO.sub.2 is in gaseous form, and in that case two consecutive orifices appear to be needed. However, expanding CO.sub.2 gas is inefficient and does not have the aggressiveness of CO.sub.2 jet spray from liquid. In using liquid CO.sub.2, two consecutive orifices are detrimental to snow production since the second orifice frequently clogs and causes sputtering of the CO.sub.2 jet spray.
Therefore, it is an objective of the present invention to provide for improved CO.sub.2 jet spray nozzles that overcome the problems of conventional CO.sub.2 jet spray nozzles.